CHM 2046 - Chemistry Fundamentals II

Final Exam Study Union Packet (Peer Tutor Lily L.)

Disclaimer: Pictures from above are from the 4th Edition of the textbook. Practice problems are modified and compiled by the tutor. They do not guarantee a good grade. They do not serve as a replacement for studying; they are a supplement.

Ch. 12

1. Which answer has the compounds ordered in terms of increasing boiling point?

a) H2 < HF < HBr < HIb) H2 < HBr < HI < HF

c) HF < HBr < HI < H2d) HF < HI < HBr < H2

2. Find the vapor pressure of a substance at 29°C whose normal boiling point is 76°C and has aof 38.7 kJ/mol.

a) 87 mmHgb) 48 mmHgc) 101 mmHgd) 96 mmHg

3. Find the amount of heat (kJ) needed to raise the temperature of a 12.0 g sample of benzene from -10°C to 25°C. (Specific heat of solid = 1.25 J/(g*°C), specific heat of liquid = 1.70 J/(g*°C), heat of fusion = 9.8 kJ/mol, melting point = 5.5°C, boiling point = 30°C)

a) 2.1 kJb) .0026 kJc) 24.4 kJd) 1.7 kJ

Ch. 13

4. Iridium crystallizes in a face-centered cubic structure with an edge length of 3.83 angstroms. Determine the density of iridium.

a) 22.4 g/cm^3 b) 12.2 g/cm^3 c) 15.0 g/cm^3 d) 2.77 g/cm^3

5. Which compound is soluble in hexane (C3H6)?

a) Waterb) CH3CH2CH3c) HCld) NH3

6. Select the answer with the largest band gap.

a) Conductorb) Semiconductorc) Nonconductord) Insulator

Ch. 14

7. Which aqueous solution has the highest freezing point?

a) 1.25 molal of C12H22O11 b) 0.5 molal of K3PO4

c) 2 molal of NaCld) 1 molal of Mg(SO4)2

8. The osmotic pressure of a solution containing 22.7 mg of an unknown protein in 50.0 mL of solution is 2.88 mmHg at room temperature. Determine the molar mass of the protein.

a) 246 g/molb) 3.85 g/molc) 2930 g/mold) 147 g/mol

9. Calculate the vapor pressure at 25°C of a solution containing 55.3 g ethylene glycol (HOCH2 CH2OH) and 285.2 g of water. (vapor pressure of pure water at 25°C = 23.8 torr)

a) 23.8 torrb) 20.9 torrc) 22.5 torrd) 25.5 torr

Ch. 16

10. In which of the following reactions will Kc equal Kp?

a) 4 NH3(g) + 3 O2(g)2 N2(g) + 6 H2(g)b) SO3(g) + NO(g)NO2(g) + SO2(g)c) 2 N2(g) + O2(g)2 N2O(g) d) O2(g) + 2 SO2(g)2 SO3(g)

11. What would increasing the pressure do to the following reaction that was previously at equilibrium? What if 3 atm of Ar is added? If this reaction is exothermic, what would raising the temperature do?2 H2O(g) + 2 SO2(g) <-> 2 H2S(g) + 3 O2(g)

Equilibrium shifts to:a) Left, No change, Rightb) No change, Right, Right

c) Left, Right, No changed) Right, Left, Right

12. Find the Kp of N2(g) + O2(g) + Br2(g) <-> 2NOBr(g) using the given info below:

NO(g) + Br2(g) <-> NOBr(g)Kp = 5.3

2NO(g) <-> N2(g) + O2(g)Kp = 2.1E30

a) 1.5E-28b) 1.4E29c) 1.3E-29d) 1.3E-32

Ch. 17

13. Find the percent ionization of 0.60 M hydrazoic acid in water. Ka = 2.5E-5.

a) 64%b) 6.4%c) 0.64%d) 0.06%

14. Find the mass of the conjugate base in 1.6 L of 0.4 M H2SO4 aqueous solution.

a) 4 gb) 26.5 gc) 38.8 gd) 64 g

15. Find the pH when 1.3 M is dissolved in an aqueous solution that initially had a pOH of 1. Kb=1.8E-4

a) 14b) 13c) 8d) 6

Ch. 18

16. A 1.0 L buffer solution contains 0.100 mol HC2H3O2 and 0.100 mol NaC2H3O2. The weak acid’s Ka is 1.8E-5. What is the pH after 0.010 moles of solid NaOH is added to the buffer?

a) 4.83 b) 2.90 c) 12.74d) 7.83

17. Find the molar solubility of calcium phosphate in a 0.10 M solution. Ksp = 2.07E-33

a) 1.14E-7b) 1.97E-11c) 3.09E-7d) 2.07E-11

18. An aqueous solution with 0.100 M of solute is titrated by 0.100 M of titrant, producing the titration curve below. With as little math possible, find the pH at the half-equivalence point and equivalence point (Hint: X is strong). pKa = 4.76

X

a) 4.76, 5.28

b) 9.25, 5.28

c) 9.25, 7.00

d) 4.76, 2.00

Ch. 19

19. Find of the reaction 2 H2S(g) + 3 O2(g) <-> 2 H2O(g) + 2 SO2(g). Individual entropies are as follows (J/(mol*K)): 205.8 205.2 188.8 248.2

a) -648 J/mol*Kb) 236 J/mol*Kc) -565 J/mol*Kd) 640 J/mol*K

20. Patino wants to produce an exergonic reaction. If H = -76 kJ and S = -555 J/K, what is the lowest possible temperature for this to happen?

a) 112 Kb) 137 Kc) 92 K d) 203 K

21. Find the ΔGrxn when T = 298 K and the pressures are such that PNO = 0.300 atm, PO2 = 0.100 atm, PNO2 = 0.500 atm. Is the reaction more or less spontaneous under these conditions than under standard conditions? 2 NO(g) + O2(g) -> 2 NO2(g) ΔG°rxn = -710.2 J

a) 6882 kJb) 6.171 kJc) 6.882 kJd) 6171.9 kJ

Ch. 20

22. Find ∆G°rxn at 25 °C. MnO2(s) + 4 H+(aq) + Cu(s) -> Mn2+(aq) + 2H2O(l) + Cu2+(aq)

∆G°f (kJ/mol)

-465.1

0 or 1517.1

0

-225.6

-237.1

65.5

a) 0.6E2 kJb) -1.7E2 kJc) -2.4E2 kJd) 2.0E2 kJ

23. Balance Cr2O7 2- + I- -> Cr 3+ + IO3 - in basic solution. What are the coefficients of OH- and H+, respectively?

a) 0, 0b) 0, 22c) 22, 22d) 22, 0

24. Copper is plated onto the cathode of an electrolytic cell containing CuCl2(aq). Calculate the amount of time needed to plate 111 mg of copper with a current of 3.8 A.

a) 89 sb) 113 sc) 44 sd) 56 s

Ch. 15

25. If N2O5’s concentration decreases by 0.065 M over 10 seconds, find the rate that oxygen gas is being formed over the same timeframe.2 N2O5(g) -> 4 NO2(g) + O2(g)

a) 0.00034 M/sb) 0.0105 M/sc) 0.00625 M/sd) 0.00325 M/s

26. A laboratory has found the rate of a reaction to be 27.1 M/s when each of the five reactants have a concentration of 2 M. The reaction orders are: second in respect to A, first for B and E, zero for C, third for D. Find k and the effect on rate if all reactant concentrations are doubled.

a) 0.21, rate is divided by 128b) 0.21, rate is multiplied by 128

c) 0.17, rate increases by 128 d) 0.17, rate is multiplied by 128

27. The decomposition of N2O takes place on a graph with a y axis of ln[A] vs and x axis of t. It has a rate constant of .76. If the initial concentration of N2O is 10.9 M, what is the concentration of N2O after 9.6 seconds?

a) 7.4E-3 Mb) 1.4E-3 Mc) 3.6E-3 Md) 8.1E-3 M

Ch. 21

28. The answer choices are all parts of a partial decay series for Th-232 that has undergone this sequence: . Identify the third step.

a) b)

c) d)

29. Find the daughter nuclide of Sr’s beta decay where A = 89 and Z = 38.

a) b) c) d)

30. Unknownium has a half-life of 4.5 years. How much will have passed for a sample to have 6.25% of its original amount?

a) 40.5 yearsb) 13.5 yearsc) 18 yearsd) 23 years

Thank you for being such wonderful tutees this semester. GOOD LUCK!